1. Field of the Invention
The present invention relates in general to containers, and more particularly, to improved features in a self-heating container.
2. Background of the Invention
In today's on-the-go consumer society, there is increasing demand for a convenient and effective container which may be used by consumers to heat consumable products, such as coffee, tea, milk, soup, and many other types of beverage or food products, at any time and any location, without having access to any conventional heating means, such as a coffee maker, microwave, cook top, etc. The self-heating technology based on an exothermic reaction between different reagents is often used in designing such containers. Under such self-heating technology, two or more reagents are initially separated by a breakable barrier, and when the heat needs to be generated, the barrier is broken to allow the mixing of the reagents, thereby creating an exothermic reaction for heat generation. Typically, the reagents employed for generating the heat include at least a solid material, such as calcium oxide, and a liquid material, such as water.
Numerous containers have been designed by use of the self-heating technology, but most have very limited use because the designs tend to be overly complicated in order to effect sufficient heat exchange, and as a result, the assembly and manufacturing of the containers may not be reasonably achievable from either a technical or business standpoint.
For example, U.S. Pat. No. 4,793,323 describes a self-heating container which includes an outer insulating envelope and a plastic material vessel provided inside the envelope, where the vessel is divided into an upper and a lower compartments separated by a membrane. The upper compartment holds a solid reagent and the lower compartment holds a liquid reagent. The upper compartment and the lower compartment are separated by an aluminum barrier which is thermally welded to a toroidal surface of the upper compartment. The container further includes a metallic inner container for holding a solid or liquid substance situated within the upper container. A breaking member is integral with the lower compartment and able to break the membrane when pressure is exerted against it. To generate heat, the container is turned upside down and a manual pressure is exerted on the bottom of the lower compartment which causes the barrier to break and the two reagents to mix, thereby generating heat. As any water present in the vicinity of the seal can adversely affect the quality of the seal, filling the lower compartment with water must be done with precision. Therefore, sophisticated testing steps in assembly of the container are required to ensure that the seal is secure. In addition, placing and securing the membrane is also complicated when there are many different parts of the container to be assembled.
Another example is PCT Publication WO 2004/022450 that describes a container including an outer container holding a beverage receptacle inserted therein. The solid reactant is arranged annularly about the beverage receptacle in the upper compartment between the outer container and beverage container, while the liquid reactant, i.e., water, is arranged in the lower compartment between the two containers. A breakable diaphragm extends substantially against the base of the beverage receptacle. A breaking device is provided within the second compartment. Again, assembly of this container is quite complicated. In particular, after the solid reactant is introduced into the outer container, a complex spinning technology has to be used to move the solid reactant in order to make room for the beverage container.
U.S. Pat. No. 6,502,407 describes a container including an external cavity which has the heating means and an internal cavity which holds the beverage. The internal cavity extends within the external cavity. The heating means includes calcium oxide placed in the internal cavity and water provided in the water chamber below the external cavity. The water chamber is separated from the heating means by the external cavity through a lid positioned in between. A plunger is affixed to a button on the base of the container. In operation, the container is inverted and the button is pressed. The depression moves the plunger in a direction to push the lid open and the water is quickly released to mix with calcium oxide in the external cavity so as to create a reaction and generate heat. Because many of the container parts need to be sealed, and seals can be easily broken when the container undergoes a temperature change, the integrity of the container can be jeopardized.
In U.S. Pat. No. 6,266,879, the disclosed container has a container body, a thermic module at one end of the body, and a closure at the other end of the body. The module has an elongated heat-exchanger portion that extends into the container body. The heat-exchanger portion has a corrugated or pleated wall to increase the surface area. A module cap is press-fit in the open end of the module body. A breakable barrier is adhesively attached to the open end of the module cap to seal a reactant inside. An actuator assembly is attached to the end of the container body and has an actuator button which is supported on spline-shaped fingers and further has a breakable actuator barrier. Pointed projections extend from the underside of outer actuator button toward the actuator barrier. In order to heat the substance inside the container, the user will depress the actuator button by exerting a force upon the button, which force then causes the fingers to puncture the barrier and causes the inner actuator button to move toward the barrier such that the distal end of the prong punctures the reaction barrier. Water flows through the barrier and mixes with solid reactant in the thermic module body. The container design in this patent is complex and involve many parts to be assembled.
Most of the existing self-heating containers, as illustrated above, are quite complex in design, expensive and difficult to manufacture, and as a result, are prohibited from being widely commercialized to accommodate most consumers. Therefore, there exists a need for an improved self-heating container to overcome the above-described deficiencies.